The 2018 hurricane season will be long remembered by us in North Florida. Back in May I predicted an average season with a high likelihood of at least one hurricane seriously impacting the United States (see earlier blog), though I had little idea it would strike with such ferocity so close to home. As it turned out fifteen tropical storms formed with eight of them going on to become hurricanes. The two most devastating–Florence and Michael–reached major hurricane intensity. Hurricane Florence made landfall in North Carolina dumping historic amounts of rain. Hurricane Michael reached the coast as the strongest hurricane ever recorded in the Panhandle, packing winds to nearly category five status. Residents from Panama City to St. George Island and inland to Marianna are still cleaning up. Memorable indeed.
Based on records kept at the National Hurricane Center, Hurricane Michael was the third-most intense Atlantic hurricane to make landfall in the contiguous United States in terms of pressure, behind only the 1935 Labor Day hurricane and Hurricane Camille of 1969. It was the strongest Atlantic hurricane to form in the month of October since Hurricane Wilma back in 2005. It was also the strongest storm in terms of maximum sustained wind speed to strike the contiguous United States since Andrew in 1992. It was also the fourth-strongest landfalling hurricane, in terms of wind speed. According to official records, Hurricane Michael caused at least 60 deaths including 45 in the United States and 15 in Central America. Michael also caused upward of $14 billion in damages and an unspecified amount of damage to the infrastructure at Tyndall Air Force Base. According to the reinsurance industry, property insurance claims in the United States will likely exceed $5 billion and losses to agriculture and timber could exceed $6 billion.
There isn’t one best way to measure the strength of a hurricane season but folks at the National Hurricane Center use accumulated cyclone energy, or ACE, which considers not only how fast the winds are blowing but for how long they blow. Stronger storms like Florence and Michael that last long contribute much more to ACE than weaker, shorter lived storms like Alberto (which also made landfall in the eastern Panhandle during May). The hurricane season finished with an above-average value for ACE. My research shows that the strongest hurricanes like Michael are getting stronger as the ocean warms (see earlier blog) but most storms encounter conditions that limit opportunities for growth. Michael went through a prolonged period of intensification and we anticipate that these periods of intensification will get longer as the warmest waters expand in coverage due to anthropogenic climate change. Let’s hope for better luck next season, but I will not bet on it.
Dr. James Elsner is the Earl & Sofia Shaw Professor and Department Chair of Geography.
The feature image is from USA Today.